Continuous connector

ABSTRACT

The present invention relates to a connector for a tubular truss assembly which is formed of tubes loosely fit between selected adjacent ones of the connectors. The tubes are held in place either by a set screw in connector receptacles into which the tubes are mounted or by a tensioning element connected between connectors for urging the connectors together. The manner of coupling and securement provides for very rapid assembly, minimization of stress concentrations and turning connector assemblies to form non-planar structures.

This is a divisional of copending application Ser. No. 07/340,861 filedon Apr. 20, 1989, now U.S. Pat. No. 5,013,176.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connector for tubular trussassemblies. More specifically, the invention relates to a connectorwhich forms a part of a truss cell wherein tubing interconnected betweenselected adjacent connectors is loosely held in the connector tofacilitate shaping the truss assembly to desired contours and fordistributing the forces and mechanical stresses existing throughout theassembly, to each member thereof.

2. Description of the Prior Art

The formation of truss assemblies using connectors of the prior artgenerally involves either the welding or bolting rigidly together of theconstituent parts of the assemblies. Examples of such assemblies areshown in U.S. Pat. No. 3,596,950, U.S. Pat. No. 4,101,230 and U.S. Pat.No. 4,343,562. With the application of strong transverse forces on thetruss assemblies described in the above patents the rigid welds tend tofracture or tear. The truss assemblies in the prior art generally willload the plate elements to which they are welded. Usually this loadingis undesirable since it may easily lead to laminar tearing of the platematerial.

Other connectors in the prior art provide rigid connectors incapable ofcontouring to form desired geometric shapes such as cylinders andsemi-spherical or completely spherical domes. Examples of suchconnectors are described in U.S. Pat. No. 1,144,491, U.S. Pat. No.3,563,580 and U.S. Pat. No. 4,076,431. In each case the resultingstructure is limited solely to specific geometric shapes such astetrahedral or fixed sloped roofs for portable car or boat storage.

The present invention remedies the deficiencies of the prior art. Theconnector includes a plurality of receptacles for receiving in a looselyfit fashion tubing which interconnects adjacent connectors. The trussassembly is maintained in a unitary structure by means of eithersecuring the tubing to the respective connector or by means of trusswires connected to selected ones of adjacent connectors and biased tourge the interconnected connectors together. The structural members ofthe truss are held in position in compression in a loose fit fashion.This unique manner of loose coupling allows slight movement of expansionand contraction and the distribution and defocusing of forces throughoutthe truss assembly.

The loose coupling diminishes the potential of fracture and tearingcharacterizing the aforementioned connectors of the prior art. Since theforces are distributed throughout the truss assembly, the undesirableconcentration of forces and stress is minimized. Because stressconcentrations are minimized lighter and weaker structural tubing can beused.

Yet another unique feature of the loosely fitting coupling of the trusstubing and connectors is the ability to "turn corners" of the surfacesit forms to create a non-planar assembly either for functional oraesthetic purposes.

To form desired structural shapes such as a cylinder it is required toturn the plane of the face of the truss assembly by the slightshortening of the tubing on the inner side of the turn desired to beformed. Spheres, domes, squares, rectangular and composite truss cellssuch as hexagonal, octagonal and the like are within the contemplationof the present invention.

Moreover the loose fitting concept which is contrary to designs of theprior art provide for rapid assembly and disassembly. The truss oncequickly assembled is less prone to the damaging effects induced bymovement of the assembly because of the "forgiveness" inherent innon-rigid structures. Once assembled, parts of the truss assembly can beremoved without collapse of the entire assembly. Thus alterations indesign during assembly is possible without substantial breakdown of theentire truss assembly.

SUMMARY OF THE INVENTION

In accordance with the invention a connector for use in a tubular trussassembly is provided having an essentially planar base portion and areceptacle means which is secured to and extends normally from the baseportion. A cover portion includes an aperture for slidable mounting onthe receptacle means. A plurality of indentations are disposed alongradii of the cover portion. The indentations open downwardly toward thebase portion for gripping the tubular truss members between the coverand base portions. Means are provided for urging the cover and baseportion together for gripping the tubular truss members therebetween.

Preferably the indentations are triangular and the cover portion isslidable on the receptacle for adapting to varying sized tubing.

Preferably the base and cover portions include paired apertures forreceiving bolt means for urging together the base and cover portions.

Preferably the base portion includes indentations similar to and inmatching relationship to the indentations of the cover portion.

Preferably a tubular truss includes a plurality of connectors and aplurality of tubes coupled to and between adjacent ones of selectedconnectors.

The truss also includes tensioning means coupled between selectedadjacent ones of the connectors for urging the connectors together.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a connector according to theinvention.

FIG. 2A is a front elevation view of the connector of FIG. 1.

FIG. 2B is a top view of the connector of FIG. 1.

FIG. 3 is a top view of an alternate embodiment of a connector accordingto the invention.

FIG. 4 is a side elevation view of the connector of FIG. 3.

FIG. 5 is a top view of still another embodiment of a connectoraccording to the invention.

FIG. 6 is a side elevation view of the connector of FIG. 5.

FIG. 7 is a perspective view of a portion of a truss assemblyincorporating connectors according to the present invention, namely theconnectors of FIGS. 5 and 6.

FIG. 8 is an elevation view of a portion of a truss assemblyincorporating connectors according to the present invention utilizingtension means between selected adjacent ones of the connectors.

FIG. 9A is a front elevation partial cutaway perspective view of a trussassembly having unequal tube lengths for forming a spherical or domelikestructure.

FIG. 9B is a sectional view of the structure of FIG. 9A along lines 9B.

FIG. 10A is an exploded perspective view of yet still another embodimentof a connector according to the invention.

FIG. 10B is a side elevation view of the connector of FIG. 10A.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings.

In particular FIGS. 1, 2A and 2B there is shown a first embodiment ofthe present invention. The connector 1 includes an essentially flat,rigid base portion 2. The base may be formed of a number of structuralmaterials such as, for example, cold rolled steel and the like. Theshape of the base portion 2 is essentially planar and as shown in FIG. 1has a circular outer periphery. As will be described later the shape ofthe outer periphery may conveniently be in the shape of othergeometrical forms such as square or truncated triangular which isusually dependent upon the number of receptacles provided in theconnector.

Extending normally from the base portion 2 is hollow tubular receptacle3. The receptacle 3 may be secured to the base 2 by conventionalattachment methods such as welding. Spaced apart bolt holes 4 areprovided in and extend through the base portion 2.

Mounted to the base and on the receptacle 3 is cover portion 5. Thecover portion 5 includes a central opening 6A which has a contoursimilar to but slightly larger than the receptacle 3. This permits thecover portion 5 to slide freely on the receptacle 3 during assemblySpaced about the cover portion 5 and with respect to base portion 2 aredownward opening indentations 6. The indentations have side walls 7 and8 and an apex 9. The apex 9 lies along a radius originating fromreceptacle axis 10. As shown best in FIG. 1 the indentations 6 aregenerally triangular in cross-section with the base of the cross-sectionbeing proximal and the apex being distal with respect to the baseportion 2.

The cover portion regions 11 which extend in the region between theindentations 6 are essentially flat and when the cover portion 5 ismounted on the receptacle 3, the regions 11 lie in a plane parallel tothe plane of the base portion 2. Disposed about the cover portion 5 arebolt holes 12 which are spaced to be coaxial with corresponding boltholes 4. In forming a continuous connector assembly, tubing 13 which isto be inserted in and secured by the connector 1, is inserted within thespace provided by the indentations 6. Advantageously the triangularcross-section permits use of variable sized tubing since the coverportion will be located in position dependent upon the size of the tube13. Thus larger sized tubing 13 will cause the cover portion 5 to bespaced further apart from the base portion 2 whereas smaller sizedtubing 13 will cause the cover portion 5 to be spaced closer to thecover portion 5. The shape of the indentations therefore provides meansfor adaptively securing varying sized tubing.

Cover portion 5 is urged towards the base portion 2, for maintainingtubes 13 therebetween in locking relationship, by means of bolts 14which are located through correspondingly aligned holes 4 in the baseportion 2 and holes 12 in the cover portion 5 and are secured in placeby means of bolt nuts 15.

As will be explained in more detail later a tension wire or brace 17 iscoupled to the connector 1 as well as to an adjacent connector forurging adjacent connectors together. As shown in FIG. 1 the brace 17 issandwiched between the base plate 2 and the cover plate 5. However, thebrace 17 may also be secured to the connector 1 on the upper surface ofthe cover plate 5 or to the lower surface of base plate 2.

For applications where it is desired to provide a less rigid and moreflexible connector, the bolts 14 may be left with a slight slack.Additionally the receptacle 3 may be reduced with respect to the tubingsize so that there is provided sufficient space for slight movement ofthe tube when located in the receptacle. For constructing contouredstructures this provision for slight relative motion or loose fitcoupling of the tubing within the connector facilitates contouring thestructure into other than planar surfaces, such as for example, slightrounded, domed, or cylindrical contours are achievable.

An alternate embodiment of the present invention is shown in FIGS. 3 and4 to which reference is now made. The connector 20 comprises asubstantially planar base plate 21 having a tubular receptacle 22 whichis normal to the base plate 21 extending along an axis 23. As shown inFIG. 3 the receptacle is circular in cross-section for receiving tubingof circular cross-section having a diameter less than that of thereceptacle. It should be noted and as will be described later, thepresent invention contemplates receptacle and tubular cross-sections inother geometrical shapes other than circular, such as, for example,square or rectangular.

Spaced apart along radii R1, R2 and R3 are second receptacles 24. Thereceptacles 24 lie in the plane parallel to the plane formed by and areattached to base plate 21. Located on the base plate 21 and spacedbetween adjacent receptacles 24 are holes 25. Securing means such asbolt 26 are mounted through the holes 25 for securing tension truss 27to the base plate 21. The tension truss 27 serves to urge togetheradjacent connectors to which it is attached. Although only one tensiontruss is shown in FIG. 3 it is to be understood that each other of theholes 25 may have a tension truss secured thereto depending upon thenature and construction of the truss assembly.

As shown in FIG. 3 tubes 28 are insertable within the receptacle 24typically through the entire length of the receptacle. A set screw 29having screw threads matching that machined in the receptacle 24 isadvancable downward to engage the tubes 28. Accordingly the receptacles28 may be, either fixedly or loosely held, within the receptacledepending upon the amount of force exerted by the set screw 29 upon thereceptacle. By such arrangement the connector provides the ability forslight movement to accommodate rounded truss structures which mayotherwise not be attainable by totally rigid connectors.

Referring now to FIGS. 5 and 6 there is shown still another embodimentof the present invention. Essentially planar base plate 30 has mountedthereon normally directed receptacle 31 and planar mounted receptacles32. Mounting the receptacles 32 to the base plate 30 may be accomplishedby any of a number of techniques such as welding. Receptacles 32 areoriented normal to each other and normal to receptacle 31. As shown inFIG. 5 and FIG. 6 the receptacles and tubing inserted therein are squarein cross-section. Set screws 34 hold the tubes 33 within the receptacle32 fixedly or loosely in accordance with the amount of tightening forceapplied to set screw 34. Disposed on the base plate 30 are through holes35. Looped through hole 35 is a truss wire 36 crimped so as to maintainthe wire coupled to the hole 35.

The truss wire 36 serves to urge together adjacent ones of selectedconnectors in a truss assembly. Although only one wire 36 is shown inFIG. 5 it is to be understood that one or more truss wires, each coupledwithin respective holes 35 is contemplated dependent upon the locationof the respective connector in the truss assembly.

Referring now to FIG. 7 there is shown two truss assembly portions 40 ofa larger truss assembly (not shown) embodying the inventive conceptsheretofore described. Connectors 41 are interconnected by means of tubes42 in "cell" arrangements comprising five connectors 41A, 41B, 41C, 41Dand 41E. Although five connectors are shown it is to be understood thatcells comprising four connectors (41E omitted in the configuration shownin FIG. 7) or three connectors or other arrangements are contemplated bythe present invention. Tubes 42 are inserted into receptacles ofadjacent connectors and secured into place by means of set screws (notshown) previously described. Each cell of five connectors is coupled toadjacent cells to then form an overall structure. Turn buckle TB1 whichis coupled between respective connectors 41A and 41B through aninterconnecting wire serves to urge connectors 41A and 41B together. Ina similar manner TB2 serves to urge connectors 41F and 41G together. Ina similar fashion additional turn buckles (not shown) may be inserted inwires between adjacent connectors to urge the respective connectorstogether. Accordingly each truss cell becomes a self-contained integralunit.

The number of cells in either the vertical or horizontal direction withrespect to FIG. 7 are added in a manner solely determined by the finalstructure desired to be assembled. Each cell provides structuralenhancement to the overall assembly and loss or damage of one cell as aresult of an unforeseen event will not markedly affect the structuralintegrity of the overall assembly. The cells in the overall assemblysupport the remaining portion of the assembly by dividing the mechanicalstresses existing in the assembly amongst a number of cells and sharingthe load from adjacent cells.

Referring now to FIG. 8 there is shown an alternative embodiment of aconnector "cell" utilizing the connector of FIG. 5. The upper cell 43includes truss wires 46 arranged in a "square" bracing arrangement withadjacent truss wires 46 coupled together at respective corners 47. Aturn buckle TB secured to one of the truss wires 46 when tightened,draws the connectors 45A, 45B, 45C and 45D together. An alternativetruss wire connection is shown in the "X" bracing arrangement of cell44. Truss wires 48 are connected between diagonally opposite connectors45B and 45F and 45A and 45E respectively. The selections of truss wirearrangements are dependent upon size and load carrying requirements ofthe truss assembly. In this manner adjacent connectors are drawntogether to establish integral connector cells in an overall trussassembly.

Referring to FIG. 9A there is shown yet another truss arrangementutilizing the connector of FIG. 3, for an assembly forming asemi-spherical or domelike contour with a cylindrical base. Trussassemblies formed in the manner shown are usable for large structuressuch as stadiums, air terminals, exhibition halls, as well as fortemporary structures such as circus tents where set-up and tear-downtimes are important considerations, without compromising the strengthrequirements of the structure. The "cell" geometry of FIG. 9A is squarewith internal brace wires in a square configuration. It is to beunderstood that other geometrical shapes such as octagonal are alsoadvantageously used in similar structures. Importantly, truss assembliesof the nature shown do not require the positive air pressure conditionsdictated by inflatable pressurized dome structures. For purposes ofclarity, except for the peripheral structure, the outer surface of thedome is not shown, but it is to be understood that the dome is formed ina semi-spherical honeycomb or "sandwich" type arrangement.

Referring to FIG. 9A and FIG. 9B, connectors 50A, 50B, 50C and 50D forma cell 54 having a square shape. The connectors 50 are urged towardseach other by truss wires 51 arranged in a square arrangement withadjacent individual truss wires 51 coupled together at respectivecorners 52. Four additional truss wires 51 couple corners 52 torespective connectors 50. Also coupled to adjacent connectors arerespective tubes 53 which complete each square shaped cell structure.

The truss wires 51 may be secured together and to the connectors 50A,50B, 50C and 50D by any one of a number of conventional techniques.Urging the connectors together may be accomplished by the use of turnbuckles interposed in the truss wires 51 or other conventionaltightening devices known in the art.

The contour shaping of adjacent cells is best illustrated by referenceto the cylindrical wall edge portion of the dome structure shown in FIG.9A. More specifically, connectors 55 and 57 are included in a truss cellthat is upstanding and forms a part of the inner surface of the base ofthe semi-spherical dome. The remaining two connectors of the cell lie inline with respective ones of the connectors 55 and 57 and therefore arenot shown. Similarly, connectors 56 and 58 are included in a truss cellthat is upstanding and forms a part of the outer surface of the base ofthe semi-spherical dome. The remaining connectors which are in line withrespective ones of connectors 56 and 58 are therefore not shown.

Corresponding facing cells forming an inner and outer portion of thedome are spaced apart a distance determined by equal length tubes 61.The curvature of adjacent cells is established by having the interiortubing 62 of a shorter length than exterior tubing 63. In this mannerwedge-shaped combinations of spaced apart cells are formed. The generalshape of the wedges are determined by the difference in interior andexterior tube lengths. Obviously the greater the difference in interiorand exterior tube lengths, the more pronounced the wedge shape. In asimilar fashion the cells which are coupled above the first row of cellsof the dome have the interior tubing of a shorter length than theexterior tubes, which results in the curving inward of the cellcombinations forming thereby a dome-like structure.

For structures desired to be cylindrical rather than spherical, then theinterior tube lengths would be less than the exterior tube lengths, butside tube lengths of the individual cells would be of equal length. Inthis manner the cell combinations would form a circumference of thecylinder but would not turn inward as in the case of the dome structure.

As mentioned previously the tubing is of similar but smallercross-section with respect to corresponding connector receptaclecross-sections. By virtue of the smaller cross-section not only is easeof assembly realized, but jamming of the tubing and the connectors isavoided and the contouring of cells and cell combinations isfacilitated. Additionally the angle between adjacent receptacles whenmade unequal provides additional flexibility to form structures otherthan planar, cylindrical or spherical.

Referring now to FIGS. 10A and 10B there is shown yet another alternateembodiment of the present invention. The connector 64 comprises twosymmetrical cover portions 65 and 66 which conform in shape and areassembled in a matching relationship. More specifically, cover portion65 is slidably mounted on hollow receptacle portion 67A and coverportion 66 is mounted on hollow receptacle portion 67B. Cover portion 65functions in a manner similar to that described for cover portion 5 ofFIG. 1 and thus will not be repeated here.

The cover portion has a plurality of indentations 68 having side walls69 and 70 and an apex 71. The apex 71 lies along a radius originatingfrom receptacle axis 72. Each indentation 68 has a triangularcross-section defined by the side walls 69 and 70 that open toward thecover portion 65. The indentations of cover portions 65 and 66 form aclosed area having a square cross-section for gripping tubing 73 heldtherebetween. Bolts 74 and 76 extend through cover portions 65 and 66respectively. Bolt nuts 77 and 86 engage bolts 76 and 85 respectivelyand upon tightening urge cover portions 65 and 66 together therebygripping tubing 73 between the cover portions. Similar boltingarrangements (not shown) are located symmetrically between the otherindentations disposed on the cover portions. As may be apparent thestructure of FIG. 10A provides for the gripping of varying sized tubing.Thus for larger sized tubing the cover portions will be held furtherapart whereas for smaller sized tubing the cover portions will be heldcloser together.

Collar 78 is slidably mounted on receptacle portion 67A and locked inplace by set screw 79. Similarly collar 80 is slidably mounted onreceptacle portion 67B and locked in place by set screw 81. In suchmanner the connectors 65 and 66 are fixed in stationary condition onreceptacles 67A and 67B, while gripping tubing 73 therebetween.

Braces 82 and 83 shown only in FIG. 10A are coupled to the connector 64either between the cover portions 65 and 66 as shown in FIG. 10A or uponthe outer surfaces of the cover portions 65 and 66. Brace 82 is securedto the connector 64 by means of bolt 74, which passes through apertures90 and 91, and nut 75 which when tightened, urges the cover plates 65and 66 together. Similarly brace 83 is secured to the connector 64 bymeans of bolt 84, which passes through apertures 88 and 89, and nut 87which when tightened urges the cover plates 65 and 66 together. Only twobraces are shown, however, it is to be understood that three or fourbraces may be used depending upon "cell" configuration. As previouslydiscussed the braces 82 and 83 are also connected to adjacent connectorsfor coupling such connectors together in a truss assembly.

I claim:
 1. A connector for interconnecting tubing comprising:a basehaving a planar surface and having a central axis orthogonal to theplane of the surface, the base having a plurality of indentations, eachindentation having a generally triangular cross-section extendingradially relative to the central axis and opening on a same, given sideof the base, the base having a plurality of apertures extendingtherethrough; receptacle means secured to and projecting from the baseon the given side thereof, said receptacle means being coaxial with thecentral axis and being shaped to receive and nonrigidly secure an end ofa piece of tubing extending along the central axis; a cover having aperipheral edge and an aperture receiving the receptacle meanstherethrough, the cover having a plurality of indentations at lest equalin number to the plurality of indentations in the base extendingradially relative to the central axis, each indentation in the coverbeing disposed radially between the aperture and the peripheral edge ofthe cover, each indentation in the cover opening toward the base havinga generally triangular cross-section and being disposed in opposedfacing relationship with an indentation in the base and providingthereby means for slideably receiving an end of a piece of tubingdisposed within the indentation between the planar surface of the baseand the cover in abutting relationship with the receptacle means, thecover having a plurality of apertures therethrough which are eachdisposed in opposed facing relationship with an aperture extendingthrough the base; and a plurality of bolts extending through theapertures through the base and cover for urging the cover toward thebase to secure in gripping relationship an end of a piece of tubingwithin a pair of opposed, facing indentations in the base and the coverand in abutting relationship with the receptacle means, and with saidend portion being in direct abutting relationship with said receptaclemeans.
 2. A tubular truss comprising:a plurality of interconnectedconnectors, each connector comprising a substantially planar base havinga substantially planar surface extending in a base plane and having acentral axis orthogonal to the base plane, first receptacle meanssecured to and projecting from the base, said first receptacle meansbeing substantially coaxial with the central axis, second receptaclemeans disposed along a surface of the planar base comprising a pluralityof hollow receptacles which each open radially outward with respect tothe central axis, the first and second receptacle means each beingsquare in cross-section and each being adapted to slideably receive atube end and maintain the received tube end therein slideable, nonrigidlocking relationship with each tube end received by a second receptaclemeans being in abutment with the first receptacle means; a plurality oftubes extending between different ones of the connectors, at least oneof the tubes extending substantially coaxially with the central axes oftwo of the connectors and having two opposite ends thereof slideablyreceived and nonrigidly secured by the first receptacle means of the twoconnectors and at least one of the tubes having two opposite endsthereof slideably received and nonrigidly secured by the secondreceptacle means of two different ones of the connectors; and tensionmeans coupled between pairs of the connectors and urging the pairs ofconnectors together to maintain the ends of the tubes in abutting andsecured relationship with the respective first receptacle means of theconnectors which receive the tube ends.
 3. A tubular truss comprising:aplurality of interconnected connectors, each connector comprising asubstantially planar base having a substantially planar surfaceextending in a base plane and having a central axis orthogonal to thebase plane, first receptacle means secured to and projecting from thebase, said first receptacle means being substantially coaxial with thecentral axis, second receptacle means disposed along a surface of theplanar base comprising a plurality of hollow receptacles which each openradially outward with respect to the central axis, the first and secondreceptacle means each being round in cross-section and each beingadapted to slideably receive a tube end and maintain the received tubeend therein slideable, nonrigid locking relationship with each tube endreceived by a second receptacle means being in abutment with the firstreceptacle means; a plurality of tubes extending between different onesof the connectors, at least one of the tubes extending substantiallycoaxially with the central axes of two of the connectors and having twoopposite ends thereof slideably received and nonrigidly secured by thefirst receptacle means of the two connectors and at least one of thetubes having two opposite ends thereof slideably received and nonrigidlysecured by the second receptacle means of two different ones of theconnectors; and tension means coupled between pairs of the connectorsand urging the pairs of connectors together to maintain the ends of thetubes in abutting and secured relationship with the respective firstreceptacle means of the connectors which receive the tube ends.
 4. Aconnector assembly for interconnecting tubing comprising:first andsecond cover portions disposed in opposed relationship about a centralaxis, each cover portion having an aperture means centered about thecentral axis and having a plurality of indentations in matching pairswhich indentations are generally triangular in cross-section and includea base portion, each indentation of the first cover portion being inopposed, facing alignment with a corresponding indentation of the secondcover portion, the corresponding indentations of each opposed pairopening towards each other to define a radially extending receptacle forreceiving an end of a radially extending piece of tubing therebetween;urging means for urging the first and second cover portions together toforce the indentations into engagement with a piece of tubing heldtherebetween to form a locking relationship and with the base portionsof the corresponding indentations in the first and second cover portionsare urged together; receptacle means extending through the aperturemeans of the first and second cover portions; and locking collar meansmountable on the receptacle means, the locking collar means comprising afirst collar in abutting relationship with the first cover portion andlockable on the receptacle means and a second collar in abuttingrelationship with the second cover portion and lockable on thereceptacle means to maintain the receptacle means in lockingrelationship with respect to the cover portion.